Improvement of Endurance Characteristics for Al-Gate Hf-Based MONOS Structures on Atomically Flat Si(100) Surface Realized by Annealing in Ar/H₂ Ambient

Abstract

In this study, the effect of atomically flat Si(100) surface on Hf-based Metal-Oxide-Nitride-Oxide-Silicon (MONOS) structure was investigated. After the atomically flat Si(100) surface formation by annealing at 1050℃/60min in Ar/4%H₂ ambient, HfO₂(O)/HfN_1.0(N)/HfO₂(O) structure with thickness of 10/3/2nm, respectively, was in-situ deposited by electron cyclotron resonance (ECR) plasma sputtering. The memory window (MW) of Al/HfO₂/HfN_1.0/HfO₂/p-Si(100) diodes was increased from 1.0V to 2.5V by flattening of Si(100) surface. The program and erase (P/E) voltage/time were set as 10V/5s and -8V/5s, respectively. Furthermore, it was found that the gate current density after the 10³P/E cycles was decreased one order of magnitude by flattening of Si(100) surface in Ar/4.0%H₂ ambient.